Since the Germans just had to re-invent the high velocity sub gun ammo wheel have there been any comparisons of the P90 ammo and the H&K MP7 ammo.

With a smaller bullet the MP7 round likely travels faster than the P90 round but it will retain less energy for CQB battle which is usually within 25 meters of less.

So... how about a Level III-A soft armor test of the two cartridges? Does this test exist anywhere outside of classified US government tests - i.e Secret Service protection detail tests and Navy DEVGRU ("Seal Team 6") tests??

A quick search reveals that Wikipedia says tests done by the UK, US, Canada and France on behalf of NATO show that the 5.7 x 28 cartridge is "undoubtedly" the superior cartridge of the two. Less temperature sensitivity, 27% better terminal performance on unprotected targets, equal penetration on "protected" (soft armored) targets and less barrel throat erosion. This comes under my heading of "Suspicions Confirmed".

Interestingly the Germans rejected these conclusions and the 4.6 round was not NATO standardized (STANAG) but this also held up NATO standardization of the 5.7 x 28 P90 round.

So with a better cartridge and most certainly a better weapon the P90 and its cartridge is STILL not NATO standardized.
The Germans love efficiency so much but this intransigence on their part is certainly not "efficient". ("Duetchland uber alles"??)

Without a civilian 4.6 gun in the US, tests are going to be hard to come by.. I can confirm smaller 4.5 rounds (17HMR) from a full length rifle barrel can penetrate soft armor. The question would be, with the restricted 4.6 ammo, how would it do.

Without a civilian 4.6 gun in the US, tests are going to be hard to come by.. I can confirm smaller 4.5 rounds (17HMR) from a full length rifle barrel can penetrate soft armor. The question would be, with the restricted 4.6 ammo, how would it do.